Amelotin pseudogenization in two toothless sauropsids. A. Location of pseudogeneized AMTN (φ AMTN) in the duck and green turtle genomes. In these two genomes, φ AMTN was found (synteny-based approach) upstream φ AMBN (ameloblastin) and φ ENAM (enamelin), all EMP genes being pseudogeneized in toothless sauropsids. B. Alignment of the nucleotide sequences of φ AMTN exons 2b and 6 of the green turtle Chelonia mydas (Cm) and the duck Anas platyrhynchos (Ap) with the corresponding coding exons of the crocodile Caiman crocodilus (Cc), their closest toothed relative. Note the few sequence variations in turtle φ AMTN exon 6. Conserved nucleotides in bold.